TYPHOID. 87 



Not only do we find hyperplasia of the endothelial cells in the 

 lymphoid tissue of Peyer's patches and the mesenteric glands and the 

 spleen, with subsequent necroses, but focal necroses of the same 

 character are found in the liver. 



A striking feature of the pathology of typhoid fever is the long- 

 continued persistence of the organisms in the gall-bladder and else- 

 where. It is beginning to be believed that a previous typhoid infection, 

 possibly so mild as to have passed unnoticed, is at the basis of gall- 

 bladder infections and resulting gall-stones. Various bone infections, 

 especially osteomyelitis, have shown the typhoid bacilli in pure culture. 

 Formerly it was supposed that the typhoid bacillus brought about its 

 lesions by a local infection centered in the ileum. The present view 

 is that typhoid bacilli effect an entrance into the blood stream through 

 some lymphoid channel, as by tonsil or other alimentary lymphoid 

 structure. It multiplies in the blood during the period of incubation and 

 it is only when bactericidal properties are developed in the blood that 

 we have destruction of the bacilli and liberation of the intracellular 

 toxins which lead to the development of symptoms. That this is 

 probable is shown by the fact that typhoid bacilli can be isolated from 

 the blood during the period of incubation. It is a practical point that 

 the time to isolate the bacteria from the blood is in the first days of the 

 attack. The diagnosis by agglutination is only expected after the 

 seventh to tenth day. Agglutination may not appear until during con- 

 valescence, and in about 5% of the cases it is absent. It, as a rule, 

 disappears within a year. Very little success has been obtained with 

 curative sera. Chantamesse, by treating horses with a filtrate from 

 cultures of typhoid bacilli on splenic pulp and human defibrinated 

 blood, claimed to have obtained a curative serum possessing antitoxic 

 power. Wright's method of prophylactic inoculation is now being 

 employed in the British army with apparent success. In this, 24- to 48- 

 hour-old cultures are killed at 53 C. ; 1/4% of lysol is then added. An 

 injection of 500 million bacteria is made at the first inoculation, and 

 ten days later an injection of one billion. The British prefer to inject 

 subcutaneously in the infraclavicular region and at the insertion of the 

 deltoid. The Germans consider three injections as conferring greater 

 immunity. 



